James Milholland was the first locomotive designer on a major railroad to put dozens of anthracite-burning locomotives in service. Warner comments that Milholland raised the firebox above the driving axles to gain the grate size needed to burn the thin bed of anthracite properly. The grate had 16 water-tube grate bars.
The Scientific American report recounts the hauling capacity of these freight haulers. Pulling 110 loaded cars (910 short tons) over a 95 run that had a fall of 620 feet, the locomotive would average 8 mph and burn about 5 tons of coal.